Tris (2-hydroxyalkyl) isocyanurates are commercial raw materials that have been used for preparing coating resins and thermosetting compositions containing an isocyanurate ring. The presence of an isocyanurate ring can improve the properties of the resins such as resistance towards thermal aging, weathering, UV light, low shrinkage, or improved mar resistance. Tris (2-hydroxyalkyl) isocyanurates can be incorporated into coating resins and thermosetting compositions as a polyol in the synthesis of polyester or polyether. However, there are disadvantages of using tris (2-hydroxyalkyl) isocyanurates, such as its higher melting point, higher viscosity, low solubility, low reactivity, and less flexible, as a polyol in the synthesis of a polyester or polyether. To overcome such disadvantages, some modified tris (2-hydroxyalkyl) isocyanurates and their derivatives have been reported. For example, U.S. Pat. No. 5,268,428 discloses the use of caprolactone and tris (2-hydroxyethyl) isocyanurates (THEIC) to prepare hydroxyl functional polyester used in binder compositions. U.S. Pat. No. 5,747,590 reported the use of caprolactone/THEIC oligomers for coating compositions. U.S. Pat. No. 7,425,594 reported copolymers produced from the reaction of glycidyl ester and/or ether with THEIC.
Tris (2-hydroxyalkyl) isocyanurates and their derivatives have also been used as cross-linking agents for epoxy and polyurethane resins. U.S. Pat. No. 4,942,215 describes a reaction product of THEIC and an equivalent quantity of one or more anhydrides, which is combined with epoxy resin and liquid anhydride in a thermosetting liquid molding composition. U.S. Pat. No. 6,667,078 describes a reaction product of acid anhydride and THEIC as a curing agent in the manufacture of a transparent resin plate for a liquid crystal display. The use of the reaction product of polycaprolactone and THEIC in a urethane coating composition has been described in U.S. Pat. No. 3,784,503.
JP Patent No. 60123478 describes an ester compound containing an isocyanuric ring having improved heat resistance and surface hardness free from brittleness, which is liquid at normal temperature and easily handleable, produced from a reaction product of epsilon (6)-caprolactone modified tris(hydroxyalkyl) isocyanurate and acrylic acid or methacrylic acid.
Tris (2-hydroxyalkyl) isocyanurates and their derivatives have also been used to produce epoxy resins. U.S. Pat. No. 3,763,097 describes a polyether epoxy resin prepared by reacting diepoxides with THEIC under the acid pH conditions. U.S. Pat. No. 5,003,040 describes modified epoxy resins prepared from the reaction of diglycidyl ether and THEIC in the presence of an etherification catalyst. The modified epoxy resin has an average of 1.5 to 2.5 epoxy groups and at least one primary hydroxyl group per molecule. A curable coating composition based on a modified epoxy resin is described in U.S. Pat. No. 5,066,763. JP Patent No. 2007099901 describes an epoxy resin with low curing shrinkage, transparency, excellent light fastness, and low yellowing under high temperatures. The epoxy resin is obtained by reacting a polycarboxylic acid compound (A) and a non-aromatic epoxy resin (B) under a basic catalyst, wherein the compound (A) is obtained by reacting tris (hydroxy alkyl) isocyanuric acid and an anhydride of a saturated acid.
Many curable resins compositions made directly with tris (2-hydroxyethyl) isocyanurate exhibit application properties that are less than desirable. For example, some compositions can result in films that do not exhibit sufficiently high strength or hardness. Other compositions can result in films that are not sufficiently flexible. Still other compositions can result in films that are brittle. Other problems, such as wrinkling or poor adhesion (which can result in delamination) can also be experienced.
It is thus an object of this invention to develop a thermosetting composition that utilizes an isocyanurate-based polyol, and is capable of producing a cured resin having the desired properties described above.